Means and methods for processing cathode ray tube bulbs



5mm. 18, 1956 R, MCKENZIE ETAL EJWfi M MEANS AND METHODS FOR PROCESSINGCATHODEI RAY TUBE BULBS Filed Nov. 25, 1955 Fzgj.

CONTROL J W 24 SPEED $4 CONTROL lnvehtorsz 'VQTW C ClafimsbeailflRobm-LT. McKenzie,

Their Attorneg,

United States Patent Ofiice 2,763,564 Patented Sept. 18, 1956 MEANS ANDMETHGDS FOR PROCESSING CATHODE RAY TUBE BULBS Robert T. McKenzie, NorthSyracuse, and Von C. Campbell, Syracuse, N. Y., assignors to GeneralElectric Company, a corporation of New York Application November 25,1953, Serial No. 394,372

22 Claims. (Cl. 117-3) Our invention relates to the processing ofcathode ray tube bulbs and pertains more particularly to new andimproved means and methods for processing the interiors of such bulbs.

In the processing of cathode ray tube bulbs the inner surface of theface plates thereof are first coated with phophorescent material toprovide a screen portion. Thereafter the screen portion is water rinsedand a lacquer film is sprayed thereover to provide a suitable base for asubsequently applied aluminum coating. In spraying the lacquer on thescreen some lacquer is deposited on the side walls of the tubes. Thislacquer must be removed completely since if even the smallest amount isleft on the side walls it will effect during a subsequent bakingoperation a peeling of an aluminum coating and paint applied to the sidewalls. Heretofore the lacquer has been first sprayed on the screenportion and then the excess lacquer has been cleaned off the side wallsby an operator using a long handled liquid-fed brush. This method provedunsatisfactory since it was messy and re quired exceptional skill on thepart of the operator to prevent splashing on the phosphorescent screenof the. hub. Additionally, it was slow and did not readily lend itselfto automation whereby production could be increased. Accordingly, aprimary object of our invention is to provide new and improved means andmethods for processing the interiors of cathode ray tube bulbs.

Another object of our invention is to provide new and improved means andmethods for spraying the screen portions of cathode ray tube bulbs withlacquer and cleaning the side walls thereof of excess lacquer.

Another object of our invention is to provide new and improved means andmethods for cleaning the side walls of cathode ray tube bulbs whichafford a relatively clean operation and require no special skill on thepart of an operator.

Still another object of our invention is to provide new and improvedmeans and methods for spraying lacquer on the screen of cathode ray tubebulb and cleaning the side walls of the bulbs of excess lacquer whichreadily lend themselves to automation and whereby production can bemarkedly increased.

Further objects and advantages of our invention will become apparent asthe following description proceeds and the features of novelty whichcharacterize our invention will be pointed out with particularity in theclaims annexed to and forming part of this specification.

In carrying out the object of our invention we provide means forspraying lacquer on the interior surface of the screen portion of acathode ray tube bulb and means for rotating the bulb with the screenportion upward. Additionally, we provide means for introducing acleaning liquid into the bulb above the lower edge of the conicalportion thereof for being caused to be centrifuged or ride up the sideof the bulb during rotation thereof. Means for controlling the rotationof the bulb determines the extent, to which the liquid rides up the sidewalls of the bulb.

For a better understanding of our invention reference may be had to theaccompanying drawing in which: Fig. 1 is a somewhat schematicillustration of means for carrying out our invention.

Fig. 2 is a partially broken away view of a cathode ray tube bulbillustrating the manner in which the lacquer is sprayed into the bulb;and Fig. 3 is a similar view illustrating the manner in which thecleaning. liquid rides up the side walls of the tube.

In Fig. l is shown a cabinet 1. Access to the interior of the cabinet isbad through a door in the front wall of the cabinet which has been cutaway to illustrate the components housed in the cabinet.

Suitably mounted on a side wall of the cabinet is a journal bracket 2.Journaled' in the bracket 2 is a cylindrical portion 3 of a rotary headgenerally designated 4. The head 4 is also formed to include a plateportion 5 disposed above the bracket 2. Mounted on the plate 5 at theedge thereof and in spaced apart relationship is a plurality of uprightbrackets 6 formed to include pad portions 7 at their upper ends. Thehead 4 is adapted for receiving a cathode ray tube bulb 3 in the mannershown in Fig. 1. The bulb 8 may be of the completely glass type or thetype including a metal cone and a glass face plate and generallyreferred to as a cathode ray tube bulb assembly. When the bulb 8 ispositioned in the head the face plate portion 9 thereof extends upward,the neck portion 10 extends downward into the cylindrical portion 3 ofthe head, and the conical portion 11 of the bulb is engaged by thebracket pads 7 for supporting the bulb' in the manner shown. Providedfor assisting in centering and securing the bulb in the head 4 is achuck generally designated 12. In a manner not fully shown, the chuck 12firmly grips the neck portion 10 of the bulb just below the lower edgeof the conical portion 11.

Also suitably secured on a wall of the cabinet 1 and provided forrotating the head 4 with the bulb secured therein is a variable speedmotor 13. The motor 13 includes a shaft 14 to which is secured a pulleywheel 15. Fitted on the pulley wheel 15 is one end of a V-belt 16. Theother end of the V-belt 16 is fitted on another pulley wheel 17 formedon the lower end of the cylindrical portion 3 of the head 4 below thebracket :2. Provided for controlling the speed of rotation of the motor13 is controlling means generally designated 18. In the arrange ment'described to this point the motor 13 is effective for rotating the head4 and the bulb 8 secured therein; and speed of rotation of the bulb iscontrollable by the motor controlling means 18.

Secured to the bottom of the cabinet 1 is a spray gun 19. As seen inFigs. 1-3 the spray gun 19 includes a vertically extending barrel 26adapted for extending into the bulb 8 through the neck portion 10thereof when the bulb is-in place in the head. The gun 19 is suppliedwith lacquer from a reservoir 21 through a line 22. The gun 19 is alsosupplied with a gas from a tank 23 through a line 24 for atomizing thelacquer in the gun to effect spraying thereof into the bulb through thebarrel 2% in the manner shown in Fig. 2. A valve 25 in the line 24controls the flow of gas from the tank to the gun. A line 26 connectsthe gas tank 23 with the lacquer line 22 whereby the gas is utilized forassisting in delivering the lacquer to the gun. A valve 27 is providedin the line 26 for controlling the flow of gas into the line 22 andthereby controlling the amount of lacquer supplied to the gun.Controlling means generally designated 28 and suitably electricallyconnected to the gun 19 is provided whereby operation of the spray gun19 can be controlled.

Also provided for extending into the bulb 8 through the neck portion 10thereof is a vertical portion 29 of a liquid line 30. The line 30 isconnected to a first liquid reservoir 31 by a tube 32 including a valve33 for controlling flow of liquid from the reservoir 31 to the line 30.The line 30 is also connected to a second reservoir 34 by a tube 35including a valve 36 for controlling flow of liquid from the secondreservoir 34 to the line 30. In this arrangement liquid can be caused toflow into the line 30 selectively from either of the reservoirs.

The end of the vertical portion 29 of the line 30 is bent horizontal andis so disposed that when the liquid is caused to flow therethrough fromeither of the reservoirs 31 or 34 it will be introduced into the bulb 8above the lower edge of the conical portion 11. Therefore, it the bulb 8is rotated in the above described manner when the liquid is introducedinto the bulb the liquid will be caused by centrifugal force to ride upthe side walls of the bulb in the manner indicated by the broken arrowheaded line 37 in Fig. 3 thereby to coat the side walls, of the bulbwith liquid in the manner shown in dot and dash lines indicated by 38 inFig. 1.

When the bulb 8 is secured in the head 4 for processing by the abovedescribed arrangement it is already provided with a phosphorescentcoating (not shown), on the inner side of the face plate 9 to provide apicture screen. It is this phosphorescent screen which it is desirous tocoat with a lacquer film to provide a suitable base for a subsequentlyapplied aluminum coating. Additionally, before applying the lacquer theinterior of the bulb is water rinsed. The application of the lacquerfilm is accomplished by means of the spray gun 19 in the manner shown inFig. 2. Spraying of the film on the screen, however, also results indeposit of excess lacquer on the inner side walls or conical portions ofthe bulb as indicated by 39 in Fig. 2. This film if left on the sidewalls will result during a subsequent baking out operation in peeling ofan aluminum coating and paint applied to the 'side walls just beforebaking. Therefore, it is desirous that the side walls of the bulb bethoroughly cleaned of lacquer before application of the aluminum coatingand paint.

The above described arrangement can be utilized for spraying the lacqueron the screen portion of the bulb and in cleaning the excess lacquerfrom the side walls of the bulb in several manners. For instance, thespray gun 19 can be energized while the bulb is rotated at a low speedfor spraying the lacquer on the screen portion of the bulb in the mannershown in Fig. 2. Thereafter the speed of rotation is increased forcausing the film to spread out by centrifugal force and thereby assume apredetermined satisfactory thinness. Then the rotation is stopped andthe excess lacquer is permitted to drain down the side walls and out theneck of the tube into a suitable receptacle (not shown). During thespraying and draining operation the side walls of the bulb become coatedwith film as indicated at 39, which for the reasons pointed out above,must be completely removed before application of an aluminum coating andpaint to the side walls. To accomplish cleaning of the side walls thebulb is again rotated and the valve 33 is opened whereby an etchingsolution which may be a solution of hydrofluoric acid and water,ammonium bifluoride or the like is permitted to flow from the reservoir31 through the tube 32 and the vertical portion 29 of the line 30 forbeing introduced into the bulb above the lower edge of the conicalportion 11. By centrifugal force rotation of the bulb 8 causes the acidsolution to ride up the side walls in the manner indicated by 37 in Fig.3 for forming a liquid coating on the side walls as indicated at 38 inFig. 1. By controlling the speed of rotation of the bulb 8 with themotor controlling means 18 the extent to which the solution rides up theside walls is determined. In riding up the side wall-s the etchingsolution works its way under the film thereon and etches the innersurface of the material comprising the side walls of the bulb.Thereafter the valve 33 is closed stopping the flow of etching solutionand rotation of the bulb is stopped permitting the soluwalls.

4 tion and lacquer cleaned off the side walls to drain out of the bulb.Thus, the lacquer is cleaned off the side walls without affecting thefilm indicated by 40 which coats the screen portion of the bulb andextends a short distance down the side walls.

In order to flush out any etching solution and lacquer which might bestill adhering to the walls of the bulb the bulb is again rotated andthe valve 36 is opened permitting water to flow from the reservoir 34into the tube 30 for being introduced into the bulb and caused to rideup the side walls of the bulb in the same manner as the etchingsolution. Again the rotations of the bulb are controlled for determiningthe extent to which the water rides up the side walls of the tube forpreventing any splashing of liquid on the phosphorescent screen of thebulb. Subsequently the rotation of the bulb is stopped and the water ispermitted to drain from the bulb for flushing out any etching andlacquer solution remaining in the bulb. This water flushing operationmay be carried out any desired number of times.

The above described arrangement may also be employed for spraying andcleaning lacquer from the side walls of the bulb in another manner. Inthis other manner the bulb may first be rotated and the etching solutionintroduced thereinto by opening the valve 33 for causing the etchingsolution to ride up the side walls of the bulb thereby to etch the sidewalls, the controlling means 18 being utilized for controlling therotation of the bulb to determine the extent to which the side walls areetched. Then the rotation is stopped to permit drainage of the solutionfrom the bulb. Thereafter the spray gun 19 is energized while the bulbis slowly turned for spraying a lacquer film onto the screen of thebulb, following which the bulb rotation is increased for thinning outthe film on the screen. In this operation some of the lacquer isdeposited on the side walls of the bulb and the bulb rotation is stoppedfor permitting the excess lacquer to drain out through the neck of thebulb. Thereafter the bulb is again rotated and water is introduced intothe bulb by opening the valve 36. Rotation of the bulb causes the Waterto ride up the side Walls. Rotation of the bulb is again controlled bythe controlling means 18 for determining the extent to which the Waterrides up the side In riding up the side walls the water is effective forwashing the lacquer film from the side walls, this being possible sincethe previous etching operation thoroughly cleaned the side walls beforethe lacquer was deposited thereon and the lacquer is thereby preventedfrom strongly adhering to the side walls. Thereafter rotation of thebulb is stopped and the water and lacquer solution are permitted todrain from the bulb. This just described water flushing arrangement maybe repeated any desired number of times.

In still another manner the arrangement shown in Fig. 1 may be employedfor spraying film inside the bulb and removing excess film from the sideWalls thereof. The bulb may be slowly rotated while the spray gun 19 isenergized and thereafter rotated faster for spreading the film on thescreen portion of the bulb. Following this the rotation is stoppedpermitting excess lacquer to drain down the side walls of the bulb andout the neck thereof. Then in order to clean the side walls of the bulba lacquer solvent may be introduced into the bulb through the tube 30from either one of the reservoirs 31 or 34. During introduction of thesolvent into the bulb the bulb is rotated whereby the solvent will becaused to ride up the side walls of the bulb by centrifugal force. Theextent to which the solvent rides up the sides of the bulb is determinedby the speed of rotation of the bulb which may be controlled by thecontrolling means 18. In riding up the side Walls the solvent dissolvesthe lacquer from the side walls and when the bulb rotation issubsequently reduced the solvent and the dissolved lacquer drain out ofthe bulb through the neck portion. This operation may be repeated anynumber of times desired and if desired a water flushing operation may beperformed in the manner described above with regard to the first twodescribed methods of processing the bulb.

While we have shown and described a specific embodiment of our inventionwe do not desire our invention to be limited to the particular formshown and described and we intend by the appended claims to cover allmodifications within the spirit and scope of our invention.

What we claim as new and desire to secure by Letters Patent of theUnited States is:

1. In a cathode ray tube bulb processing machine, means for supporting abulb with the face portion thereof upward, means for introducing aliquid into said bulb in the vicinity of the lower edge of the conicalside Wall portion of said bulb, and means for rotating said bulb tocause said liquid to ride up said side wall portion of said bulb.

2. In a cathode ray tube bulb processing machine, means for supporting abulb with the face portion thereof upward, means for introducing aliquid into said bulb in the vicinity of the lower edge of the conicalside wall portion of said bulb, means for rotating said bulb to causesaid liquid to ride up said side wall portion of said bulb, and meansfor controlling the speed of said bulb rotating means to determine theextent to which said liquid rides up said conical side wall portion.

3. In a cathode ray tube bulb processing machine, for supporting a bulbwith the screen portion thereof upward, means for spraying a film intosaid bulb and onto said screen portion, means for introducing a cleaningliquid into said bulb, and means for rotating said bulb to cause saidcleaning liquid to ride up the side wall portion of said bulb forcleaning excess film material from the side walls of said bulb.

4. In a cathode ray tube bulb processing machine, means for supporting abulb with the screen portion thereof upward, means for spraying a filminto said bulb and onto said screen portion, means for introducing acleaning liquid into said bulb, means for rotating said bulb to causesaid cleaning liquid to ride up the side wall portion of said bulb forcleaning excess film material from the side walls of said bulb and meansfor controlling the speed of said bulb rotating means to determine theextent to which said liquid rides up said conical side wall portion.

5. In the processing of cathode ray tube bulbs; the method consisting inthe steps of supporting a bulb with the face portion upward andcentrifuging a liquid up the side wall portions of said bulb to providea liquid coating on the side wall portions of said bulb.

6. In the processing of cathode ray tube bulbs, the method consisting inthe steps of supporting a bulb with the face portion upward,centrifuging a liquid up the side wall portions of said bulb to providea liquid coating on the side wall portions of said bulb, and controllingthe said centrifuging to determine the extent of said coatmg.

7. In the processing of cathode ray tube bulbs, the method of cleaningthe side wall portions of a bulb consisting in the steps of supporting abulb with the face portion upward, introducing a cleaning liquid intosaid bulb in the vicinity of the lower edge of the conical side wallportion thereof, and rotating said bulb to cause said liquid to ride upsaid conical side wall portion of said bulb.

8. I11 the processing of cathode ray tube bulbs, the method of cleaningthe side wall portions of a bulb consisting in the steps of supporting abulb with the face portion upward, introducing a cleaning liquid intosaid bulb in the vicinity of the lower edge of the conical side wallportion thereof, rotating said bulb to cause said liquid to ride up saidconical side wall portion of said bulb, and controlling the rotation ofsaid bulb to determine the extent to which said liquid rides up saidconical side wall portion.

9. In the processing of cathode ray tube bulbs, the

6 method of cleaning the side wall portions of a bulb consisting in thesteps of supporting a bulb with the face portion upward, introducing anetching solution into said bulb, and rotating said bulb to cause saidsolution to ride up the side wall portion of said bulb for etching andthereby cleaning the side walls of said bulb.

10. In the processing of cathode ray tube bulbs, the method of cleaningthe side wall portions of a bulb consisting in the steps of supporting abulb with the face portion upward, introducing an etching solution intosaid bulb, rotating said bulb to cause said solution to ride up the sidewall portion of said bulb for etching and thereby cleaning the sidewalls of said bulb, and controlling the rotation of said bulb todetermine the extent to which said side walls are etched.

11. In the processing of cathode ray tube bulbs, the method of cleaningthe side wall portions of a bulb consisting in the steps of supporting abulb with the face portion upward, introducing an etching solution intosaid bulb, rotating said bulb to cause said solution to ride up the sidewall portion of said bulb for etching and thereby cleaning the sidewalls of said bulb, reducing said rotation of said bulb to drain saidetching solution and matter cleaned from said side walls from said bulb,introducing water into said bulb, again rotating said bulb to cause saidwater to rideup said side wall portion for washing any remaining acidsolution and other matter from the side walls of said bulb and reducingsaid rotation of said bulb to drain said water from said bulb wherebysaid remaining etching solution and other matter are flushed from saidbulb.

12. In the processing of cathode ray tube bulbs, the method of cleaningthe side wall portions of a bulb consisting in the steps of supporting abulb with the face portion upward, introducing an etching solution intosaid bulb, rotating said bulb to cause said solution to ride up the sidewall portion of said bulb for etching and thereby cleaning the sidewalls of said bulb, controlling the rotation of said bulb to determinethe extent to which said side walls are etched, reducing said rotationof said bulbs to drain said etching solution and matter cleaned fromsaid side walls from said bulb, introducing water into said bulb, againrotating said bulb to cause said water to ride up said side wall portionfor washing any remaining etching solution and other matter from saidside walls, again controlling the rotation of said bulb to determine theextent to which said water rides up said side wall portion, and againreducing said rotation of said bulb to drain said water from said bulbwhereby said remaining etching solution and other matter are flushedfrom said bulb.

13. In the processing of cathode ray tube bulbs, the method of coatingthe screen of a bulb with lacquer and cleaning the side wall portions ofsaid bulb of excess lacquer deposited thereon consisting in the steps ofsupporting said bulb with the screen upward, spraying said lacquer intosaid bulb and onto said screen, introducing an etching solution intosaid bulb, and rotating said bulb to cause said solution to ride up saidside wall portion of said bulb for etching the side walls of said bulbto remove lacquer therefrom.

14-. In the processing of cathode ray tube bulbs, the

method of coating the screen of a bulb with lacquer and cleaning theside wall portions of said bulb of excess lacquer deposited thereonconsisting in the steps of supporting said bulb with the screen upward,spraying said lacquer into said bulb and onto said screen, introducingan etching solution into said bulb, rotating said bulb to cause saidsolution to ride up the side wall portion of said bulb for etching theside walls of said bulb to remove lacquer therefrom, and controlling therotation of said bulb to determine the extent to which said solutionrides up said side wall portion thereby to determine the extent to whichsaid lacquer is removed from said side walls.

15. In the processing of cathode ray tube bulbs, the

method of coating the screen of a bulb with lacquer and cleaning theside wall portions of said bulb of excess lacquer deposited thereonconsisting in the steps of supporting said bulb with the screen upward,spraying a lacquer into said bulb and onto said screen, introducing anetching solution into said bulb, rotating said bulb to cause saidsolution to ride up the side wall portion of said bulb for etching theside walls of said bulb to remove lacquer therefrom, reducing rotationof said bulb to drain said etching solution and removed lacquer fromsaid bulb, introducing water into said bulb, again rotating said bulb tocause said water to ride up said side wall portion for washing anyremaining etching solution and lacquer from said side walls, andreducing said rotation of said bulb to drain said water from said bulbwhereby said remaining etching solution and removed lacquer are flushedfrom said bulb.

16. In the processing of cathode ray tube bulbs, the method of coatingthe screen of a bulb with lacquer and cleaning the side wall portions ofsaid bulb of excess lacquer deposited thereon consisting in the steps ofsupporting said bulb with the screen upward, spraying a lacquer intosaid bulb and onto said screen, introducing an etching solution intosaid bulb, rotating said bulb to cause said solution to ride up the sidewall portion of said bulb for etching the side walls of said bulb toremove lacquer therefrom, controlling the rotation of said bulb todetermine the extent to Which said solution rides up said side wallsthereby to determine the extent to which said lacquer is removed fromsaid side walls, reducing rotation of said bulb to drain said etchingsolution and removed lacquer from said bulb, introducing water into saidbulb, again rotating said bulb to cause said Water to ride up said sidewalls for washing any remaining etching solution and removed lacquerfrom said side walls, again controlling said rotation of said bulb todetermine the extent to which said water rides up said side wallportion, and again reducing said rotation of said bulb to drain saidwater from said bulb whereby said remaining etching solution and removedlacquer are flushed from said bulb.

17. In the processing of cathode ray tube bulbs, the method of coatingthe screen of a bulb with lacquer and cleaning the side wall portions ofsaid bulb of excess lacquer deposited thereon consisting in the steps ofsupporting said bulb with the screen upward, introducing an etchingsolution into said bulb, rotating said bulb to cause said solution toride up the side walls portion of said bulb for etching said side walls,reducing rotation of said bulb to drain said etching solution from saidbulb, spraying a lacquer into said bulb and onto said screen,introducing water into said bulb, again rotating said bulb to cause saidWater to rise up said side wall portion for washing said lacquer fromsaid etched side walls, and reducing said rotation of said bulb to drainsaid water from said bulb whereby said removed lacquer is flushed fromsaid bulb.

18. In the processing of cathode ray tube bulbs, the method of coatingthe screen of a bulb with lacquer and cleaning the side wall portions ofsaid bulb of excess lacquer deposited thereon consisting in the steps ofsupporting said bulb with the screen upward, introducing an etchingsolution into said bulb, rotating said bulb to cause said solution toride up the side wall portion of said bulb for etching said side walls,controlling the rotation of said bulb to determine the extent to whichsaid solution rides up said side wall portion thereby to determine theextent to which said side walls are etched, reducing rotation of saidbulb to drain said etching solution from said bulb, spraying a lacquerinto said bulb and onto said screen, introducing water into said bulb,again rotating said bulb to cause said water to ride up said side wallportion for washing said lacquer from said etched side Walls, againcontrolling rotation of said bulb to determine the extent to which saidwater rides up said side wall portion, and again reducing said rotationof said bulb to drain said water from said bulb whereby said removedlacquer is flushed from said bulb.

19. In the processing of cathode ray tube bulbs, the method of removingsoluble matter from the side Wall portions of a bulb consisting in thesteps of supporting said bulb with the face portion upward, introducinga solvent of the matter to be removed from said side walls into saidbulb, rotating said bulb to cause said solvent to ride up said side wallportion of said bulb for dissolving said matter from the side walls ofsaid bulb, and reducing rotation of said bulb to drain said solvent andsaid dissolved matter from said bulb.

20. In the processing of cathode ray tube bulbs, the method of removingsoluble matter from the side wall portions of a bulb consisting in thesteps of supporting a bulb with the face portion upward, introducing asolvent of the matter to be removed from said side walls into said bulb,rotating said bulb to cause said solvent to ride up said side wallsportion of said bulb for dissolving said matter from the side walls ofsaid bulbs, controlling the rotation of said bulb to determine theextent to which said solvent rides up said side walls for dissolvingsaid matter from said side Walls, and reducing rotation of said bulb todrain said solvent and said dissolved matter from said bulb.

21. In the processing of cathode ray tube bulbs, the method of coatingthe screen of a bulb with lacquer and cleaning the side wall portions ofsaid bulb of excess lacquer deposited thereon consisting in the steps ofsupporting said bulb with the screen upward, spraying a lacquer intosaid bulb and onto said screen, introducing a lacquer solvent into saidbulb, rotating said bulb to cause said solvent to ride up the side wallportion of said bulb for dissolving said lacquer from the side Walls ofsaid bulb, and reducing rotation of said bulb to drain said solvent anddissolve lacquer from said bulb.

22. In the processing of cathode ray tube bulbs, the method of coatingthe screen of a bulb with lacquer and cleaning the side wall portions ofsaid bulb of excess lacquer deposited thereon consisting in the steps ofsupporting said bulb with the screen upward, spraying a lacquer intosaid bulb and onto said screen, introducing a lacquer solvent into saidbulb, rotating said bulb to cause said solvent to ride up the side Wallportion of said bulb for dissolving said lacquer from the side walls ofsaid bulb, controlling the rotation of said bulb to determine the extentto which said solvent rides up said side wall por tion thereby todetermine the extent to which said lacquer is dissolved from said sideWalls, and reducing rotation of said bulb to drain said solvent anddissolved lacquer from said bulb.

References Cited in the file of this patent UNITED STATES PATENTS2,619,430 Fink Nov. 25, 1952

1. IN A CATHODE RAY TUBE BULB PROCESSING MACHINE, MEANS FOR SUPPORTING ABULB WITH THE FACE PORTION THEREOF UPWARD, MEANS FOR INTRODUCING ALIQUID INTO SAID BULB IN THE VICINITY OF THE LOWER EDGE OF THE CONICALSIDE WALL PORTION OF SAID BULB, AND MEANS FOR ROTATING SAID BULB TOCAUSE SAID LIQUID TO RIDE UP SAID SIDE WALL PORTION OF SAID BULB.